Sodium bicarbonate has long been recognized for its deodorant properties, and has commonly been used as a deodorant in refrigerators. In addition, plain powdered sodium bicarbonate or diluted with talc, cornstarch, rice-flour, or other filler has been used as an underarm deodorant as disclosed in the Journal of Investigative Dermatology Vol. 71946 pages 131-133 and U.S. Pat. No. 279,195 and No. 1,558,405.
Aqueous ethanol solutions of sodium or potassium bicarbonate as deodorant products have also been disclosed in British Pat. No. 1,553,739. Although said bicarbonate solutions are efficacious deodorants, underarm irritation has been observed at the 10% level of potassium bicarbonate. It has also been found that aqueous or aqueous/alcoholic sodium bicarbonate solutions are pH unstable.
Aging studies have shown that the bicarbonate in solution breaks down liberating CO.sub.2 and gradually converts into sodium carbonate (a known skin irritant). Bicarbonate solutions also have solubility limitations. Proportionately larger amounts of water are required for higher bicarbonate levels. Consequently less alcohol is permitted which results in wetter, slower drying products. Also, the preparation of sodium bicarbonate solutions above 6.9% are impossible due to its limited water solubility.
The prior art also discloses aerosol suspensions, dispensed via a pressurized container, containing sodium bicarbonate slurried with propellants in a 50:50 mixture in U.S. Pat. No. 2,959,225; and alkali metal bicarbonate in a 0.3 to 15% propellant-soluble vehicle such as ethanol with about 90% propellant in British Pat. No. 1,476,117. The difficulties and disadvantages encountered with aerosol suspensions of sodium or potassium bicarbonate discussed in aforesaid patents, include the settling and/or agglomeration of the dry particles, clogging of the dispensing nozzle, non-uniform spray of deodorant material, nonadherence of the bicarbonate deodorant to the sprayed area due to the bounce-off of said dry powder and/or too wet a spray resulting in too long a drying time, in addition to being detrimental to the environment.
Cosmetic sticks containing antiperspirants and/or sodium bicarbonate suspended in a solid vehicle of a water-insoluble alcohol, such as cetyl alcohol and a silicone oil, is disclosed in U.S. Pat. No. 4,126,679. The difficulty of using sodium bicarbonate in this stick is due to its decomposition into sodium carbonate at relatively low temperatures as clearly shown in this patent.
However, there is no disclosure of a stable pituitous sodium or potassium bicarbonate suspension in an alcoholic aqueous media containing hydroxyethyl cellulose as the essential suspending agent, which requires usually no shaking prior to use, which substantially differs from the prior art aqueous or aqueous alcoholic solutions, aerosol suspensions and solid stick suspensions.